The death of a spouse is a very common experience in old age, and predicts immediate elevation of mortality risk for the surviving spouse. Although public health interventions cannot eliminate exposure to the "risk factor" of widowhood, we can potentially remediate the detrimental health consequences arising out of the experience of widowhood. Approximately 14% of American men and 44% of women over age 65 are widows or widowers. Preserving the health of surviving spouses is important to families, clinicians, and the public health community. In recognition of the broad implications of the "widowhood effect" (i.e., the increased risk of mortality among individuals following spousal loss), many studies have focused on showing the presence of such an effect across populations. However, the nature and magnitude of widowhood effects are likely to be contingent on the social context of the surviving spouse. Identifying these modifiers is an important first step in designing interventions to buffer the adverse effects of widowhood on health and mortality. Very little prior research has systematically examined whether there are differential effects of widowhood by individual's social context whether measured at the individual or community level. Further, we understand little about the important physiologic mediators, which may differ for the short or long-run effects of widowhood. The goals of this proposal are therefore to (I) identify aspects of individual and community social context that reduce the health consequences of widowhood;and (II) elucidate the physiologic basis for the observed association between widowhood and mortality. We will utilize the data from the Health and Retirement Study (HRS), which is an on-going nationally representative and longitudinal study of health and aging of Americans over the age of 50 supported by the National Institute of Aging (NIA). The HRS with exceptionally rich measures of individual and community variables also provides a unique opportunity to distinguish the widowhood effect from the confounding by common causes of spousal and own health;a major concern in prior studies showing a widowhood effect. The HRS has been not been fully utilized for understanding the effects of widowhood particularly in relation to measuring individual and neighborhood modifiers as well as the use of biomarkers. This R21 proposal is intended to provide a cornerstone for a larger research project investigating the importance of 'sensitive'or 'critical'periods in middle and late adulthood by identifying factors at the individual, family, neighborhood, metropolitan, or state levels that foster successful navigation of these periods and ultimately foster successful and healthy aging. PUBLIC HEALTH RELEVANCE: The death of a spouse is a very common experience in old age, and predicts immediate elevation of mortality risk for the surviving spouse. The goals of this proposal are to find characteristics of the individual or the neighborhood in which the individual lives that may reduce the effects of bereavement on the surviving spouse's health. We will also examine whether losing one's spouse predicts changes in physiologic indicators of health.